It was apparently offered for sale to media in the UK, Germany and France, with a price tag of 60,000 Swiss Francs - around £40,000.

The theft has been reported to police who are investigating the incident which is believed to have happened at Grenoble Hospital.

Schumacher's manager Sabine Kehm strongly appealed to the media not to publish the data.

She threatened legal action if any of the information - said to contain contain details of Schumacher's surgical procedures - was made public.

She said: “For several days stolen documents and data are being offered for sale. The offeror claims them to be the medical file of Michael Schumacher.

“We cannot judge if these documents are authentic. However, the documents are clearly stolen. The theft has been reported. The authorities are involved.

“We expressly advise that both the purchase and the publication of such documents and data is forbidden. The contents of any medical files are totally private and confidential and must not (be) made available to the public.

“We will therefore, in every single case, press for criminal charges and damages against any publication of the content or reference to the medical file. We trust for your understanding.”

Ms Kehm added: "As you can imagine we are horrified and disgusted.".

It is not clear if the alleged notes originated from Grenoble Hospital, in France, or from University Hospital Lausanne, in Switzerland.

It is 25 weeks since Schumacher suffered his life-threatening accident while holidaying with family and friends in Meribel, where he owns a chalet.

He was skiing with his 14-year-old son on a red piste, which is classed for intermediate skiers, but skied on to an off-piste area and struck a partially-covered rock, losing control and catapulting 34 feet on to another rock.

He smashed his head on the bolder, with the force of the collision shattering his helmet, and doctors placed him in an induced coma.

The hospital in Lausanne where he was transferred last week is just 20 miles from the home of the seven-time F1 champion.

He lives in a mansion worth £50 million on the shores of Lake Geneva with his devoted wife Corinna and their children Mick, 14, and Gina Marie, 17, who have been a constant presence at his hospital bedside.